The Osirion or Osireon is an ancient Egyptian temple. It is located at Abydos, to the rear of the Mortuary Temple of Seti I.
It is an integral part of Seti I's funeral complex and is built to resemble an 18th Dynasty Valley of the Kings tomb. It was discovered by archaeologists Flinders Petrie and Margaret Murray, who were excavating the site in 1902–03. The Osirion was originally built at a considerably lower level than the foundations of the temple of Seti, who ruled from 1294 to 1279 BC. While there is disagreement as to its true age, Peter Brand says it "can be dated confidently to Seti's reign".Strabo, who visited the Osireion in the first century BC, said that it was constructed by Ismandes, or Mandes, the same builder as the Labyrinth at Hawara:
Coordinates 26°11'2.861" N 31°55'6.271" E